Simple objective-c question - function that returns a string

Question

Hi,

Silly as it may sound, I am trying to write a simple fuction in objective-c which returns a string and displays it, the following code nearly works but I can't get printf to accept the functions return value ...

NSString* getXMLElementFromString();

int main(int argc, char *argv[])
{
    printf(getXMLElementFromString());
    return NSApplicationMain(argc,  (const char **) argv);
}

NSString* getXMLElementFromString() {
    NSString* returnValue;
    returnValue = @"Hello!";
    return returnValue;
}

Any help out there would be much appreciated.

Richie.

Answer 1

I don't know that printf can handle an NSString. Try somethign like:

 printf ("%s\n", [getXMLElementFromString()cString]);

Answer 2

You should instead use NSLog() which takes a string (or a format string) as a parameter.

You could use either

NSLog(getXMLElementFromString());

or

NSLog(@"The string: %@", getXMLElementFromString());

Where the %@ token specifies an Objective-C object (in this case an NSString). NSLog() works essentially the same as printf() when it comes to format strings, only it will also accept the object token.

Answer 3

NSString* is not equivalent to a traditional C string, which is what printf would expect. To use printf in such a way you'll need to leverage an NSString API to get a null-terminated string out of it:

printf("%s", [getXMLElementFromString() UTF8String]);